Investment Securities - Schedule of Proceeds from Sales or Calls and Realized Gain and Losses of Available-for-sale Investment Securities and Other Securities (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales of investment securities available-for-sale	$ 236,410	$ 8,681
Proceeds from calls of available-for-sale debt securities	436,742	145,356
Total	400,181	32,366
Realized gains on sales of available-for-sale debt securities	5,595	71
Realized losses on sales of available-for-sale debt securities	(409)	(148)
Net debt securities gains (losses)	5,174	(103)
Calls
Debt Securities, Available-for-sale [Line Items]
Proceeds from calls of available-for-sale debt securities	163,771	23,685
Realized gains on calls of available-for-sale debt securities	13	3
Realized losses on calls of available-for-sale debt securities	$ (25)	$ (29)

The gross profit realized on the call of available-for-sale debt or equity securities.

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The gross loss realized on the call of available-for-sale debt or equity securities.

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Amount of unrealized and realized gain (loss) on investment in debt and equity securities.

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Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of cash inflow from maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of cash inflow from sale, maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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